Process of developing photographic pictures.



Nrrn STATES A'rnnrr OFFICE.

ARTHUR EIOHENGRUN AND KARL DEMELER, OF ELBERFELD, GERMANY, ASSIGNORS TO FARBENFABRIKEN OF ELBERFELD 00., OF NEvV YORK, N. Y., A CORPORATION OF NElV YORK.

PROCESS OF DEVELOPING PHOTOGRAPHIC PICTURES.

SPECIFICATION forming part of Letters Patent No. 696,019, dated March 25, 1902.

Application filed August 5,1901. SerialNo. 70,926- (No specimens.)

T ztZZ whom, if; may concern:

Be it known that we, ARTHUR EIOHENGRIJN and KARL DEMELER, doctors of philosophy, chemists, residing at Elberfeld, Germany, (assignors to the FARBENFABRIKEN OF EL- BERFELD 00., of New York,) have invented certain new and useful Improvements in Processes of Developing Photographic Pictures, of which the following is a specification.

Ve have found that the amidooxybenzyl alcohols, their ethers and esters, having the following general formula:

(in which formula R means hydrogen, an alkyl or acidyl radical, such as methyl, ethyl, acetyl, or the like,) are especially suitable :0 for developing photographic pictures on glass, celluloid, paper, (he, prepared with silver chlorid, bromid,or iodid, or with two or all of these salts, after proper exposure to light. The production of the said amidooxybenzyl alcohols is described in a separate application for Letters Patent bearing the same date.

The new products used in the usual Way develop quickly without the use of caustic alkalies, which are in many ways unsuitable 0 in photography, and in this way they are superior to the developers hitherto employed. The pictures produced by the new-developers show extraordinary brilliancy, great detail, and strong contrast and possess a color which insures rapid printing. Another special advantage of our new developers is that plates, &c., may be left in the developing-baths for any reasonable length of time and no fear of fog need be entertained.

In carrying out our new process practically we can proceed as follows: Ten grams of sodium sulfite are dissolved in one hundred cubic centimeters of water and into the resulting solution one gram of finely powdered hydrochlorid of amidoparaoxybenzyl alcohol is introduced. For use sixty cubic centimeters of this solution is mixed with twenty cubic centimeters of a twenty-per-cent. solution of potassium carbonate.

The developing-bath is prepared in an analogous mannerif other of the above-mentioned amido compounds are used.

Instead of sodium sulfite, sodium pyrosulfite, and instead of potassium, carbonate acetone may be used.

Having thus described our invention and in What manner the same is to be performed, what we claim as new, and desire to secure by Letters Patent, is

1. The herein-described process of developing photographic pictures by means of amido compounds having the hereinbefore-defined general formula:

substantially as hereinbefore described.

2. The herein-described process of developing photographic pictures consisting in subjecting them to the action of a solution containin g amidoparaoxybenzyl alcoho1,substantially as hereinbefore described.

3. The herein-described process of developing photographic pictures consisting in subj ecting them to the action of an aqueous solution containing amidoparaoxybenzyl alcohol hydrochlorid sodium sulfite and potassium carbonate, substantially as hereinbefore described.

In testimony whereof we have signed our names in the presence of two subscribing witnesses.

ARTHUR EICHENGRUN. KARL DEMELER. Witnesses:

Or'ro KoNIG, FRITZ Unnns.

It is hereby certified that in Letters Patent No. 696,019, granted March 25, 1902, upon the application of Arthur Eichengriin and Karl Demeler, of Elberfeld, Germany, for an improvement in Processes of Developing Photographic Pictures, an error appears in the printed specification requiring correction, as follows: Line 77, after the Word alcohol, the comma should be stricken out and inserted after the Word hydrochlorid, line 78; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Ofiice.

Signed, countersigned, and sealed this 8th day of April, A. 1)., 1902.

[SEAL] F. L. CAMPBELL,

Assistant Secretary of the Interior.

Oountersigned F. I. ALLEN,

Commissioner of Patents. 

